Headgear assemblies and headgear liners having friction-reducing interface elements

ABSTRACT

Headgear, helmets, and related protective equipment having friction reducing interface elements are provided. The headgear includes a helmet shell having external surface and an internal surface; a headgear liner shaped and adapted to be received by the helmet shell, the head gear liner having an external surface positioned to contact the internal surface of the helmet shell; and at least one interface element positioned between the external surface of the headgear liner and the internal surface of the helmet shell. The at least one interface element provides at least some reduction in friction between the external surface of the headgear liner and the internal surface of the helmet shell. The headgear liner may comprise a fluid-filled headgear liner. The interface elements may provide surfaces at multiple elevations that assist in dispersing an impact load to the headgear liner. Methods of protecting the wearer of the headgear are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from pending U.S. Provisional PatentApplication 63/036,006, filed on Jun. 8, 2020; and from pending U.S.Provisional Patent Application 63/198,714, filed on Nov. 6, 2020, thedisclosures of which are included by reference herein in their entirety.

BACKGROUND OF THE INVENTION Technical Field

Aspects of the present invention relate generally to head protection andthe minimization and prevention of head injury. More particularly,aspects of the invention, in their several embodiments, provide helmets,headgear, headgear liners, and helmet assemblies havingfriction-reducing and/or load-directing interface elements or padsbetween the headgear liner and the helmet shell.

Description of Related Art

Numerous human activities, such as, recreation and sports, construction,public protection, and armed services expose the human body, especially,the head, to impact and injury. Head injury can be the most traumatictype of bodily injury. Especially when in motion, the exposure of thehuman head to contact and injury can be a continuous concern, whetherthe head motion is while in a motorized vehicle or while on a bicycle orwalking beneath an active building site. Many attempts have been made inthe art of head protection to minimize damage to the skull, brain, andbrain stem due to head impact.

Many prior art attempts to address this concern have yielded varioushelmet designs that provide impact energy absorbing materials, forexample, foam rubbers and plastics, in an attempt to provide as much“cushioning” material between the surface of impact and the head.Accordingly, in the state of the helmet art in the early 21st century,it is typical to provide as much foam cushioning within a helmet withoutdetracting from the aesthetic appearance of the helmet. The resultinghelmets have been limited in their success in meeting either goal ofhead protection or aesthetics.

U.S. Pat. No. 8,856,972 of Kirshon first introduced the concept ofliquid-filled, fluid-displaced liner technology to the art. Thistechnology was further enhanced as disclosed in U.S. Pat. No. 10,531,699of Kirshon. This technology is marketed by KIRSH Helmets of Schenectady,New York under the trademarks Fluid Displacement Liner™ technology andFDL™ technology. Though the inventions disclosed in the '972 and the'699 patents provide effective means for dissipating impact loading,further improvements and advantages are provided by aspects of thepresent inventions.

SUMMARY OF THE INVENTION

Aspects of the present invention provide helmets, headgear, and headgearliners having interface elements or pads that direct loading and/orreduce friction, or enhance slippage, between the headgear liner and thehelmet shell to provide enhanced head protection in a broad range ofhelmet applications and other barrier protection applications. Accordingto some aspects, interrace enhanced head protection in a broad range ofhelmet and other barrier protection applications.

The present invention employs improved helmets or headgear and headgearliners that accommodate the latest improvements in impact diffusing,fluid-filled headgear liner technology. These headgear and headgearliners include mechanisms, devices, and/or means elements may channelloads on the helmet shell in desired directions to provide for reducingfriction between the headgear liner and the internal surface of theheadgear to improve headgear and headgear liner performance, forexample, under impact loading. Aspects of the invention may also includemechanisms, devices, and/or means to regulate, direct, or channel thetransfer of loads, for example, impact loads, from the helmet shell tothe fluid-filled liner to enhance the dissipation and absorption ofimpact forces and energy directed upon the head of the wearer.

Testing of prototype helmet assemblies having liquid-filled headgearliners positioned in helmet shells revealed that friction between thesurface of external liner and the internal surface of the helmet shellmay affect the impact absorbing capacity of the helmet assembly.Subsequent testing revealed that reducing this friction, or allowing theheadgear liner to move or “slip,” for example, locally slip in thevicinity of an impact, while in contact with the internal surface of thehelmet shell, may improve the energy absorbing or dissipating capacityof the helmet assembly. Aspects of the present invention includemechanisms and means for reducing friction between the headgear linerand the internal surface of the helmet shell to enhance the protectivecapacity of a helmet assembly. Testing also revealed that theseinterface elements can also provide a means to regulate or channel thetransfer of loads, for example, impact loads, from the helmet shell tothe fluid-filled liner to enhance the dissipation and absorption ofimpact forces and energy and reduce the forces directed upon the head ofthe wearer.

Aspects of the present invention include mechanisms and means forreducing friction between the headgear liner and the internal surface ofthe helmet shell and/or mechanisms and means for reducing the loadstransferred to enhance the protective capacity of a helmet assembly.

Aspect of the present invention are not limited for use in helmettechnology, but are envisioned to be applicable to any form ofprotective barrier, for example, body armor or any form of surfaceprotection.

One embodiment of the invention is a helmet or headgear assemblycomprising or including: a helmet shell shaped to generally conform tothe head of a wearer, the helmet shell having an external surface and aninternal surface; a headgear liner, for example, a fluid-filled liner,shaped and adapted to be received by the helmet shell, the head gearliner having an external surface; and at least one interface elementpositioned between the external surface of the headgear liner and theinternal surface of the helmet shell, the at least one interface elementproviding at least some reduction in friction between the externalsurface of the headgear liner and the internal surface of the helmetshell.

In one aspect, the at least one interface element may comprise a firstsurface positioned to face the helmet shell and at least one secondsurface positioned to face the helmet shell, the at least one secondsurface distal the first surface. In one aspect, the impact by a load onthe helmet shell in a vicinity of the at least one interface elementtransmits a first portion of the load to the first surface, through theat least one interface element, and into the headgear liner in a firstdirection, and transmits a second portion of the load to the at leastone second surface, through the at least one interface element, and intothe headgear liner in a second direction, different from the firstdirection. In another aspect, the at least one second surface of the atleast one interface element comprises a second surface facing the helmetshell at a first distance from the helmet shell and a third surfacefacing the helmet shell at a second distance, greater than the firstdistance.

In one aspect, the at least one interface element may be a plurality ofinterface elements mounted to the internal surface of the helmet shelland/or to the external surface of the headgear liner.

In one aspect, the at least one interface element may be a flexiblematerial mounted to the external surface of the headgear liner by anadhesive, a mechanical fastener, or stitching.

In one aspect, the headgear liner may be a flexible, fluid impermeableenclosure having opposing end walls, a sidewall extending between theopposing end walls, and a fluid contained in the enclosure.

In one aspect, the at least one interface element may be ahook-and-loop-type fastener, for example, a hook-and-loop-type fastenermounted to the external surface of the headgear liner.

In one aspect, the at least one interface element may be two opposingloop sides of hook-and-loop-type fasteners.

In one aspect, the headgear assembly may be a helmet, for example, abaseball catcher's helmet, a baseball batter's helmet, a soft ballcatcher's helmet, a softball batter's helmet, a hockey helmet, a hockeygoalie mask, a motorcycle helmet, a motor cross helmet, a skiing helmet,a snowboarding helmet, a skateboarding helmet, a lacrosse helmet, abicycle helmet, a jockey helmet, an official's helmet, a medicalprotection helmet, a rock or ice climbing helmet, a mountain climbinghelmet, a football helmet, a hardhat, or a military helmet.

In one aspect, the headgear may be a “bump cap,” as known in the art.For example, when the situation and/or head clearance discourage the useof a conventional helmet, such as, a hard hat, a smaller and, typically,less obtrusive “bump cap” may be worn to provide the head of the wearerwith at least some impact protection, for example, in tight quarters. Asknown in the art, bump caps may have a shell sized and shaped to conformto the internal shape of helmet shell or to the internal shape of aconventional “baseball cap,” for example, with or without a “visor,” andinclude some form of internal liner and/or suspension beneath the shellproviding head protection not typically provided by conventional helmetshells, baseball caps, or similar headgear. In one aspect of thisinvention, the interface elements disclosed herein may comprise a bumpcap positioned between a helmet shell and a helmet liner, for example, afluid-filled liner.

In one aspect, the at least one interface element may extend over morethan 50% of a surface area of the external surface of the headgearliner. In another aspect, the at least one interface element may extendover more than 80% of the surface area of the external surface of theheadgear liner, for example, in one aspect, the at least one interfaceelement may be a “bump cap,” as known in the art.

In one aspect, the at least one interface element may further include aplurality of projections or pins from the internal surface of the atleast one interface element, for example, from the internal surface ofbump cap, and wherein the headgear liner may include a plurality ofrecesses or holes, each of the plurality of recesses or holes positionedand adapted to engage one of the plurality of projections or pins. Therecesses or holes in the headgear liner may be through holes. In oneaspect, the engagement of the plurality of projections or pins with theplurality of recesses or holes at least partially retains the headgearliner within the at least one interface element, for example, a bump capfunctioning as an interface element.

Another embodiment of the invention is a headgear liner assemblycomprising or including: a headgear liner comprising a flexible, fluidimpermeable enclosure having opposing end walls, a sidewall extendingbetween the opposing end walls, and a fluid contained in the enclosure;and at least one interface element mounted to the headgear liner, the atleast one interface element providing at least some reduction infriction between the headgear liner and an internal surface of a helmetshell into which the headgear liner is positioned.

In one aspect, the at least one interface element of the headgear linermay comprise a first surface positioned to face a helmet shell and atleast one second surface positioned to face the helmet shell, the atleast one second surface distal the first surface. In one aspect, theimpact by a load on the helmet shell in a vicinity of the at least oneinterface element transmits a first portion of the load to the firstsurface, through the at least one interface element, and into theheadgear liner in a first direction, and transmits a second portion ofthe load to the at least one second surface, through the at least oneinterface element, and into the headgear liner in a second direction,different from the first direction. In another aspect, the at least onesecond surface of the at least one interface element may comprise asecond surface facing the helmet shell at a first distance from thehelmet shell and a third surface facing the helmet shell at a seconddistance, greater than the first distance.

In one aspect, the at least one interface element on the headgear linermay be a hook-and-loop-type fastener mounted to the external surface ofthe headgear liner. For example, the at least one interface element maybe two opposing loop sides of a hook-and-loop-type fasteners.

Another embodiment of the invention is a helmet or a bump cap having theheadgear liner described above.

In one aspect, the at least one interface element of the headgear linerassembly may extend over more than 50% of a surface area of an externalsurface of the headgear liner, or more than more than 80% of the surfacearea of the external surface of the headgear liner, for example, whereinthe at least one interface element may comprise a bump cap.

In another aspect, the at least one interface element of the headgearliner assembly may include a plurality of projections or pins from theinternal surface of the at least one interface element, and wherein theheadgear liner may include a plurality of recesses or holes, each of theplurality of recesses positioned and adapted to engage one of theplurality of projections or pins. In one aspect, the engagement of theplurality of projections or with the plurality of recesses or holes mayat least partially retain the headgear liner within the at least oneinterface element.

A further embodiment of the invention is a method of protecting thehead, the method comprising or including: mounting at least oneinterface element to an external surface of a headgear liner or aninternal surface of a helmet shell, the at least one interface elementproviding at least some reduction in friction between the externalsurface of the headgear liner and the internal surface of the helmetshell; inserting the headgear liner into the helmet shell where the atleast one interface element is positioned between the external surfaceof the headgear liner and the internal surface of the helmet shell; andpositioning the helmet shell with headgear liner and the at least oneinterface element onto the head of a user.

In one aspect, the method may further include, upon impact of a load onthe helmet shell in the vicinity of the at least one interface element,allowing the helmet shell to move relative to the headgear liner and/orinterface element. The relative movement may comprise at least somecircumferential or transverse movement between the internal surface ofthe helmet shell and the external surface of the headgear liner. It isunderstood that such relative movement can improve the distribution ofthe impact load to the liner, for example, improve the distribution ofthe impact load to the fluid of a fluid-filled liner, and thus attenuateor reduce the loading on the head of the wearer.

In another aspect, the interface element may include a first surfacepositioned to face the helmet shell and at least one second surfacepositioned to face the helmet shell, the at least one second surfacedistal the first surface, wherein the method further comprises, uponimpact by a load on the helmet shell in a vicinity of the interfaceelement, allowing a first portion of the load to impact the firstsurface and transmit the first portion of the load through the interfaceelement and into the headgear liner in a first direction, and allowing asecond portion of the load to impact the at least one second surface andtransit the second portion of the load through the interface element andinto the headgear liner in a second direction, different from the firstdirection. In one aspect, the at least one second surface may comprisethe second surface and a third surface, wherein the method furthercomprises allowing a third portion of the load to impact the thirdsurface and transmit the third portion of the load through the interfaceelement and into the headgear liner in a third direction, different fromthe first direction and the second direction. According to one aspect ofthe invention, the first, the second, and/or the third directions may begenerally transverse or substantially parallel to the external surfaceof the headgear liner. However, it is believed that at least a componentof the first, the second, and/or the third direction may also bedirected radially, for example, a component of the first, the second,and/or the third direction may be directed substantially perpendicularto the external surface of the headgear liner.

In one aspect, the method may further comprise, upon impact by a load onthe helmet shell in a vicinity of the at least one interface element,reducing transmission of the load to the head of the user compared to aload transmitted to the head when no interface element is provided.

A further embodiment of the invention is a method for dispersing loadingupon a barrier to a fluid-containing liner, the method comprising orincluding: positioning an interface element between a barrier (forexample, a helmet shell, a body armor panel, or a stadium wall) and afluid-containing liner, the interface element having a first surfacefacing the barrier and at least one second surface facing the barrier,the at least one second surface distal the first surface; allowing thebarrier to be impacted by a load in the vicinity of the interfaceelement; transmitting a first portion of the load upon the barrier tothe first surface and through the interface element to thefluid-containing liner in a first direction; and, after transmitting thefirst portion to the first surface, transmitting a second portion of theload to the at least one second surface of the interface element andthrough the interface element to the fluid-containing liner in a seconddirection, different from the first direction.

In one aspect, the at least one second surface of the interface elementmay comprise a second surface facing the barrier at a first distancefrom the barrier and a third surface facing the barrier at a seconddistance greater than the first distance.

In another aspect, the fluid-containing liner may comprise a flexible,hollow liner encasing a fluid. In one aspect, at least one of the firstdirection and the second direction comprises a direction substantiallyparallel to a plane of the first surface. As noted herein, according toone aspect of the invention, at least a component of the first, thesecond, and/or the third direction may also be directed radially, forexample, substantially perpendicular to the external surface of theinterface element.

In another aspect, the method further comprises allowing the interfaceelement and/or fluid-containing liner to at least partially moverelative to the barrier, for example, by reducing the friction due tothe at least partial movement of the interface element relative to thebarrier.

In one aspect, the step of positioning the interface element between thebarrier and the fluid-containing liner may comprise positioning aplurality of interface elements, that is, more than one, where each ofthe plurality of interface elements has a first surface facing thebarrier and at least one second surface facing the barrier, the at leastone second surface distal the first surface. For example, in one aspect,positioning the plurality of interface elements comprises positioning aplurality of interface elements wherein each of the plurality comprisesa first surface directed in a first direction from the other firstsurfaces of the other interface elements of the plurality of interfaceelements.

Another embodiment of the invention is a device for dispersing loadingon a barrier (for example, a helmet shell or body armor panel) upon afluid-containing liner, the device comprising or including: an interfaceelement adapted to be positioned between a barrier and afluid-containing liner, the interface element having a first surfacepositioned to face the barrier and at least one second surfacepositioned to face the barrier, the at least one second surface distalthe first surface; wherein, when positioned between the barrier and thefluid-containing liner, impact by a load on the barrier in a vicinity ofthe interface element transmits a portion of the load to the firstsurface, through the interface element, and into the fluid-containingliner in a first direction, and then transmits a second portion of theload to the at least one second surface, through the interface element,and into the fluid-containing liner in a second direction, differentfrom the first direction.

In one aspect, the barrier may be a protective panel, such as, a helmetshell, a knee pad, a shoulder pad, a shin pad, or any other bodilyprotection or body armor, an athletic barrier (such as, a stadium wallor stanchion), military body armor or police body armor, among otherprotective apparel.

In one aspect, the at least one second surface of the interface elementmay comprise a second surface facing the barrier at a first distancefrom the barrier and a third surface facing the barrier at a seconddistance greater than the first distance.

In one aspect, the fluid-containing liner may comprise a flexible hollowliner encasing a fluid, for example, an oil, or an alcohol.

In one aspect, the device may comprise a friction-reducing material, forexample, a polytetrafluoroethylene (PTFE) material.

In one aspect, the device may further comprise a base element havingguide members, wherein a first of the guide members comprises the firstsurface and a second of the guide members comprises the second surface.In one aspect, the guide members may comprise projections from the baseelement.

In one aspect, the interface element may comprise a plurality of piecesof hook-and-loop type fasteners.

These and other aspects, features, and advantages of this invention willbecome apparent from the following detailed descriptions of the variousaspects of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention will be readily understood from thefollowing detailed description of aspects of the invention taken inconjunction with the accompanying drawings in which:

FIG. 1 is a top perspective view of a helmet or headgear assemblyaccording to one aspect of the invention.

FIG. 2 is an exploded perspective view of the helmet or headgearassembly shown in FIG. 1.

FIG. 3 is an exploded perspective view of the headgear liner assemblyshown in FIG. 2.

FIG. 4 is a plan view of one interface element shown in FIG. 3 accordingto one aspect of the invention.

FIG. 5 is a side elevation view of the interface element shown in FIG.4.

FIG. 6 is a top perspective view of a helmet or headgear assemblyaccording to another aspect of the invention.

FIG. 7 is an exploded perspective view of the helmet or headgearassembly shown in FIG. 6.

FIG. 8 is a top plan view of a liner assembly that may be used for theliner assembly shown in FIGS. 6 and 7.

FIG. 9 is a top plan view of another liner assembly that may be used forthe liner assembly shown in FIGS. 6 and 7.

FIG. 10 is a front perspective view of the liner assembly shown in FIG.9.

FIG. 11 is a top plan view of one interface element shown in FIGS. 8 and9 according to one aspect of the invention.

FIG. 12 is a side elevation view of the interface element shown in FIG.11 as viewed along view lines 12-12 in FIG. 11.

FIG. 13 is a side elevation view of the interface element shown in FIG.11 as viewed along view lines 13-13 in FIG. 11.

FIG. 14 is an exploded perspective view of the interface element shownin FIG. 11.

FIG. 15 is a plan view of a portion of the headgear liner assemblyidentified by Detail 15 shown in FIGS. 8 or 9.

FIG. 16 is a cross-sectional view of the portion of the headgear linerassembly shown in FIG. 15 as viewed along view lines 16-16 in FIG. 15.

FIG. 17 is another plan view of the portion of the headgear the linerassembly shown by Detail 15 shown in FIGS. 8 or 9.

FIG. 18 is a cross-sectional view of the portion of the headgear linerassembly shown in FIG. 17 as viewed along section lines 18-18 in FIG.17.

FIG. 19 is a top plan view of another interface element shown in FIGS. 8and 9 according to an aspect of the invention.

FIG. 20 is a side elevation view of the interface element shown in FIG.19 as viewed along view lines 20-20 shown in FIG. 19.

FIG. 21 is a side elevation view of the interface element shown in FIG.19 as viewed along view lines 21-21 shown in FIG. 19.

FIG. 22 is a top plan view of another interface element shown in FIGS. 8and 9 according to an aspect of the invention.

FIG. 23 is a side elevation view of the interface element shown in FIG.22 as viewed along view lines 23-23 shown in FIG. 22.

FIG. 24 is a side elevation view of the interface element shown in FIG.22 as viewed along view lines 24-24 shown in FIG. 22.

FIG. 25 is a perspective view of a helmet assembly according to afurther aspect of the invention.

FIG. 26 is an exploded perspective view of the helmet assembly shown inFIG. 25.

FIG. 27 is a plan view of the fluid-filled helmet liner shown in FIG.26.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a top perspective view of a helmet or headgear assembly 10according to one aspect of the invention. FIG. 2 is an explodedperspective view of the helmet or headgear assembly 10 shown in FIG. 1.In the following disclosure of the invention, though assembly 10 and itscomponents may be referred to as a “helmet assembly,” a “helmet shell,”or a “helmet,” it is envisioned and understood that assembly 10 maycomprise any form of “headgear,” that is, not specifically a protectivehelmet. For example, aspects of the invention may be applicable to anyform of headwear, protective or otherwise, including pump caps, asdisclosed herein. It is also envisioned that aspects of the inventionmay be applicable to any form of protective barrier, for example, bodyarmor or any form of surface protection.

As shown in FIGS. 1 and 2, in one aspect, headgear assembly 10 includesa helmet shell 12 and a helmet or headgear liner assembly 14. Accordingto one aspect of the invention, headgear liner assembly 14 may comprisea headgear liner 16, for example, a fluid-filled headgear liner asdisclosed in U.S. Pat. No. 8,856,972 and U.S. Pat. No. 10,531,699, or inpending U.S. application Ser. No. 16/595,135 filed on Oct. 7, 2019;pending U.S. application Ser. No. 16/738,234, filed on Jan. 9, 2020;pending U.S. application Ser. No. 17/020,888, filed on Sep. 15, 2020;and pending U.S. application Ser. No. 17/015,738, filed on Sep. 9, 2020,the disclosures of which are incorporated by reference herein in theirentirety. These and related helmet or headgear liners are marketed underthe trademark Fluid Displacement Liner™ technology by Kirsh Helmets. Inother aspects, headgear liner 16 may be any headgear or helmet lineradapted to be received by a helmet shell, such as, helmet shell 12.Helmet shell 12 includes an internal surface 18 and an external surface19, and liner 16 includes an external surface 20.

In order to facilitate disclosure of the invention, in FIGS. 1 and 2,helmet shell 12 is shown transparent to allow illustration of the linerassembly 14 and its components positioned within helmet shell 12.However, as is typical in the art, helmet shell 12 may be opaque, and betinted, for example, with an aesthetically appealing color or design,though shell 12 may be transparent or translucent. Helmet shell 12 maytypically be made of plastic, for example, a polycarbonate, such as, apolycarbonate shell fabricated by injection molding, or an equivalentprocess. In one aspect, helmet shell 12 may comprise one of the helmetsor helmet shells shown in U.S. Design Pat. Nos. 844,252; 853,038;877,986; and 869,778, which are included by reference herein.

According to aspects of the invention, helmet assembly 10 includes someform of mechanism, device, or means for reducing the friction betweenhelmet shell 12 and headgear liner 16. Specifically, aspects of theinvention include some form of mechanism, device, or means for reducingthe friction between internal surface 18 of helmet shell 12 and theexternal surface 20 of headgear liner 16. In one aspect, the device forreducing the friction may comprise any interface, interfaces, structure,or structures positioned between internal surface 18 of helmet shell 12and the external surface 20 of headgear liner 16. In one aspect, thefriction-reducing interface, interfaces, structure, or structures mayextend over at least a portion of internal surface 18 and/or over atleast a portion of external surface 20. In another aspect, thefriction-reducing interface, interfaces, structure, or structures mayextend over a substantial portion (for example, more than 50% of thesurface area) of internal surface 18 and/or over a substantial portionof external surface 20. In another aspect, the friction-reducinginterface, interfaces, structure, or structures may extend substantiallycompletely over (for example, more than 80% of the surface area)internal surface 18 and/or substantially completely over externalsurface 20. See FIGS. 25 and 26 for an example of an interface elementextending substantially completely over the external surface of afluid-filled liner. In one aspect, the interface, interfaces, structure,or structures between internal surface 18 of helmet shell 12 and theexternal surface 20 of headgear liner 16 may comprise a materialcharacterized by providing reduced friction, for example, apolytetrafluoroethylene (PTFE), such as, a DuPont Teflon® PTFE, or itsequivalent, or a Saint-Gobain Rulon® PTFE, or its equivalent.

In is envisioned that aspects of the invention may provide at least 5%reduction in friction, for example, at least a 5% reduction in thecoefficient of friction (static or dynamic) between internal surface 18of helmet shell 12 and the external surface 20 of headgear liner 16.However, it is envisioned that aspects of the invention may provide atleast a 10% reduction in coefficient of friction, or at least a 20%reduction in the coefficient of friction between internal surface 18 ofhelmet shell 12 and the external surface 20 of headgear liner 16.

In one aspect of the invention, the reduction in the coefficient offriction may be provided by a fluid, for example, an oil-based lubricantor the like. In another aspect of the invention, the reduction in thecoefficient of friction may be provided by a solid, for example, agraphite powder or the like.

In one aspect, the internal surface 18 of helmet shell 12, the externalsurface 20 of headgear liner 16, or both may be treated, for example,chemically or mechanically, to enhance the reduction in friction betweenthe mating surfaces. For example, the internal surface 18 of helmetshell 12, the external surface 20 of headgear liner 16, or both may besanded or polished to provide reduced friction. In another aspect, theinternal surface 18 of helmet shell 12, the external surface 20 ofheadgear liner 16, or both may be coated with the friction reducingcompound, such as, a PTFE-containing compound, or the like.

In one aspect of the invention, as shown in FIG. 2, at least one, buttypically a plurality of interface elements or “pads” 22 may be providedto surface 20 to provide at least some reduction in friction betweeninternal surface 18 of helmet shell 12 and the external surface 20 ofheadgear liner 16. FIG. 3 is an exploded perspective view of theheadgear liner assembly 14 shown in FIG. 2 with interface elements orpads 22 isolated from the liner 16. As shown in FIGS. 2 and 3, headgearliner 16, for example, a fluid-filled headgear liner may have aplurality of through holes 24. Headgear liner 16 may also have aplurality of radial slots 26 allowing the liner 16 to conform to, forexample, manipulated and positioned into, the internal shape of helmetshell 12.

As shown in FIG. 2, in one aspect, interface elements or pads 22 may bepositioned on surface 20 of headgear liner 16 where the pads 22 at leastpartially cover or bridge a radial slot 26 in liner 16. In one aspect,pads 22 may be mounted or fixed, for example, with an adhesive, to oneside of a radial slot 26 in liner 16 while not being fixed or mounted tothe other side of radial slot 26. For example, in one aspect, a pad 22may be mounted to a surface on one side of a radial slot 26 while alsobeing allowed to “float” or slide with little or no restriction on thesurface of the opposite other side of slot 26. It is envisioned thatallowing at least a portion of pad 22 to float, permits the pad 22 to beminimally affected by any separation or relative movement of thesurfaces adjacent slot 26 and without deflecting, stretching, orstressing pad 22. In one aspect of the invention, pads 22 may befabricated from an elastic material, for example, one or more of therubbers or elastomers disclosed herein, and thus accommodate anyrelative movement of surfaces adjacent slots 26.

The interface elements or pads 22 may be mounted to the internal surface18 of helmet shell 12, to the external surface 20 of headgear liner 16,or to both surfaces. Pads 22 may be mounted to the internal surface 18of helmet shell 12 or the external surface 20 headgear liner 16 with anadhesive, one or more mechanical fasteners, stitching, or thermal fusion(for example, welding), and the like. In one aspect, interface elementsor pads 22 may not be fixed to either surface 18 or surface 16 but beallowed to “float” between surfaces while providing the desiredreduction in friction.

Interface elements or pads 22 may comprise a broad range of materialsand material surface textures. For example, in one aspect, pads 22 maycomprise a plastic, for example, a polyamide (PA), for example, nylon; apolyethylene (PE), both high-density polyethylene (HDPE) and low-densitypolyethylene (LDPE); a polyethylene terephthalate (PET); a polypropylene(PP); a polyester (PE); a polytetrafluoroethylene (PTFE); a polystyrene(PS); an acrylonitrile butadiene styrene (ABS); a polycarbonate (PC); ora polyvinylchloride (PVC); among other plastics. In another aspect, pads22 may comprise an elastic material, such as, a rubber or an elastomer,for example, a natural polymer, such as, polyisoprene rubber, or asynthetic polymer, such as, a neoprene, a thermoplastic elastomer, athermoplastic rubber, and a polyvinyl chloride, or an ethylene propylenediene monomer (EPDM) rubber, and the like. In another aspect, pads 22may comprise a wood (for example, in the form of paper) or a metal whileproviding the desired reduction in friction.

In one aspect, pads 22 may provide a substantially smooth surfaceagainst the mating or opposing surface. In another aspect, pads 22 mayprovide an irregular surface, for example, one with projections,undulations, asperities, or “hills and valleys,” for instance, providingisolated points or regions of contact with the mating or opposingsurface.

In the aspect of the invention shown in FIG. 3, interface elements orpads 22 may be flexible or pliant, for example, readily conforming tothe shape and texture of the internal surface 18 of helmet shell 12and/or the external surface 20 of headgear liner 16. In one aspect, pads22 may comprise a woven or unwoven fabric, for example, a natural fabricsuch as, cotton or wool, or a synthetic fabric, for example, fabricatedfrom threads of any one or more of the plastics or polymers disclosedherein.

In one aspect, pads 22 may be fabricated from hook-and-loop-typefastener materials, for example, a Velcro® hook-and-loop-type fastenermaterial. In one aspect, the hook-and-loop-type fastener material may bemounted to internal surface 18 of helmet shell 12 and/or to externalsurface 20 of headgear liner 16 wherein either the “loop-side” or the“hook side” of the hook-and-loop-type material may bear against theopposing surface. For example, in one aspect, pads 22 may comprisehook-and-loop-type fastener material where the pad 22 may be mounted tothe external surface 20 of headgear liner 16 where either the loop sideor the hook side may bear against the opposing internal surface 18 ofthe helmet shell 12. In one aspect, pads 22 may be mounted to theexternal surface 20 of headgear liner 16 where the hook side of thehook-and-loop-type fastener may bear against the opposing internalsurface 18 of the helmet shell 12. In one aspect, pads 22 may comprise ahook-and-loop-type fastener material comprising opposing “hook side” and“loop side,” where one side provides a mounting to the surface 18 orsurface 20 (via a corresponding hook-and-loop-type fastener mounted tosurface 18 or surface 20) and the opposing side provides thefriction-reducing bearing surface against surface 18 or surface 20, asappropriate. Alternative arrangements of the mounting of “loop-side” orthe “hook side” of a hook-and-loop-type material to internal surface 18and/or to external surface 20 may be apparent to those of skill in theart.

FIG. 4 is a plan view of one interface element 22 shown in FIG. 3according to one aspect of the invention and FIG. 5 is a side elevationview of the interface element 22 shown in FIG. 4. In one aspect of theinvention, interface element or pad 22 may assume a broad range ofgeometric shapes while providing the desired reduction in friction.These shapes include circular, rectangular, square, elliptical, or anyconventional polygonal shape.

In the aspect of the invention shown in FIGS. 4 and 5, pad 22 is shownin a general rounded rectangular shape or “race track oval” type shape.As shown in FIG. 4, pad 22 may have a dimension 28, that is, a length, awidth, or a diameter, ranging from 0.25 inches to 12 inches, depending,among other things, upon the size of liner 16, but typically has adimension 28 ranging between 1 inch and 3 inches.

As shown in FIG. 5, pad 22 may typically have rounded ends, though inother aspects, the ends may not be rounded, and a thickness 30. Thethickness 30 of pad 22 may range from 0.0625 inches to 2 inches,depending, among other things, upon the size of liner 16, but typicallythickness 30 ranges between 0.125 inches and 0.5 inches.

In one aspect of the invention, as shown in FIG. 5, pad 22 may comprisetwo components 32 and 34 mated along an interface 36 (shown by a dashedline). Components 32 and 34 may be substantially the same materiel ordifferent materials. In one aspect, interface 36 may comprise anadhesive mating the components 32 and 34.

In one aspect, components 32 and 34 may each comprise ahook-and-loop-type fastener material, for example, the same or adifferent hook-and-loop-type fastener material. For instance, in oneaspect, components 32 and 34 may comprise a “hook side,” a “loop side,”or both of a hook-and-loop-type faster material, wherein the interface36 comprises the backing adhesive that may typically be provided withhook-and-loop-type fasteners. In one aspect, interface elements or pads22 may comprise components 32 and 34 each having a “hook side” surfaceof the hook-and-loop-type fastener while mated along interface 36 thusexposing the “hook side” surface on either side of pads 22 for bearingagainst and reducing friction with a mating surface. In one aspect, thedual component pad 22 shown in FIG. 5 may be mounted to surface 18and/or surface 20 with an adhesive, a mechanical fastener, and/or acorresponding hook-and-loop-type faster mounted to surface 18 and/orsurface 20.

The hook-and-loop-type fasteners used for pad 22 may comprise a plastichook-and-loop-type fastener, for example, a nylon hook-and-loop-typefastener, or a hook-and-loop type fastener made of any one of theplastics disclosed herein. In one aspect, the hook-and-loop typefastener used for pad 22 may be a Velcro® brand hook-and-loop-typefastener provided by Velcro, USA, for example, a nylon loop Velcro®hook-and-loop-type fastener having model number 158505, or itsequivalent.

FIG. 6 is a top perspective view of a helmet or headgear assembly 50according to another aspect of the invention. FIG. 7 is an explodedperspective view of the helmet or headgear assembly 50 shown in FIG. 6.As discussed with respect to headgear assembly 10, in the followingdisclosure of this aspect of the invention and throughout thisdisclosure, though assembly 50 and its components may be referred to asa “helmet assembly,” a “helmet shell,” or a “helmet,” it is envisionedand understood that assembly 50 may comprise any form of “headgear,”that is, not specifically a protective helmet. For example, aspects ofthe invention may be applicable to any form of headwear, protective orotherwise, including pump caps, as disclosed herein. It is alsoenvisioned that aspects of the invention may be applicable to any formof protective barrier, for example, body armor or any form of surfaceprotection.

As shown in FIGS. 6 and 7, in one aspect, headgear assembly 50 includesa helmet shell 52 and a helmet or headgear liner assembly 54 positionedwithin shell 52. According to one aspect of the invention, headgearliner assembly 54 may comprise a headgear liner 56, for example, afluid-filled headgear liner as disclosed in any one of the cited USpatents or pending US applications incorporated by reference herein. Inother aspects, headgear liner 54 may be any headgear or helmet lineradapted to be received by a helmet shell, such as, helmet shell 52.Helmet shell 52 includes an internal surface 58 and an external surface59, and liner 56 includes an external surface 60.

As shown in FIGS. 6 and 7, headgear liner 56 may have a plurality ofthrough holes 64 and headgear liner 56 may also have a plurality ofradial slots 66 allowing the liner 56 to conform to, for example, bemanipulated and positioned into, the internal shape of helmet shell 52.

In order to facilitate disclosure of the invention, in FIGS. 6 and 7,helmet shell 52 is shown transparent to allow illustration of the linerassembly 54 and its components positioned within helmet shell 52.However, as is typical in the art, helmet shell 52 may typically beopaque, and be tinted, for example, with an aesthetically appealingcolor or design, though shell 52 may be transparent or translucent.Helmet shell 52 may typically be made of plastic, for example, apolycarbonate, such as, a polycarbonate shell fabricated by injectionmolding, or an equivalent process. In one aspect, helmet shell 52 maycomprise one of the helmets or helmet shells disclosed in U.S. DesignPat. Nos. 844,252; 853,038; 877,986; and 869,778, which are included byreference herein.

According to aspects of the invention, helmet assembly 50 includes someform of mechanism, device, or means for reducing the friction betweenhelmet shell 52 and headgear liner 56 and/or some form of mechanism,device, or means for directing the transmission of loading upon thehelmet shell 52 to the headgear liner 56 to enhance energy absorptionand minimize the loading directed to the head of the wearer, not shown.Specifically, though in some aspects of the invention some form ofmechanism, device, or means may be provided for reducing the frictionbetween internal surface 58 of helmet shell 52 and the external surface70 of headgear liner 56, for example, as disclosed in pendingapplication Ser. No. 17/020,888, aspects of the present inventionprovide an interface, interfaces, structure, or structures positionedbetween internal surface 58 of helmet shell 52, or any helmet shelldisclosed herein, and the external surface 70 of headgear liner 56, orof any headgear liner disclosed herein, adapted to direct or “channel”any loading on the helmet shell 52 in a preferred direction upon theheadgear liner 56 to enhance the absorption of energy by the headgearliner 56 and/or by the helmet assembly 50.

In one aspect, the load channeling provided by the interface,interfaces, structure, or structures may extend over at least a portionof internal surface 58 and/or over at least a portion of externalsurface 60. In another aspect, the load channeling interface,interfaces, structure, or structures may extend over a substantialportion (for example, more than 50% of the surface area) of internalsurface 58 and/or over a substantial portion of external surface 70. Inanother aspect, the friction-reducing and/or the load-directinginterface, interfaces, structure, or structures may extend substantiallycompletely over (for example, more than 80% of the surface area of)internal surface 58 and/or substantially completely over externalsurface 60. In one aspect, the interface, interfaces, structure, orstructures between internal surface 58 of helmet shell 52 and theexternal surface 60 of headgear liner 56 may comprise a materialcharacterized by providing reduced friction, for example, apolytetrafluoroethylene (PTFE), such as, a DuPont Teflon® PTFE, or itsequivalent, or a Saint-Gobain Rulon® PTFE, or its equivalent.

In is envisioned that aspects of the invention may provide at least 5%reduction in friction, for example, at least a 5% reduction in thecoefficient of friction (static or dynamic) between internal surface 58of helmet shell 52 and the external surface 60 of headgear liner 56.However, it is envisioned that aspects of the invention may provide atleast a 10% reduction in coefficient of friction, or at least a 20%reduction in the coefficient of friction between internal surface 58 ofhelmet shell 52 and the external surface 60 of headgear liner 56.

In one aspect of the invention, as shown in FIG. 7, at least one, buttypically a plurality of interface elements or “pads” 62 may be providedto provide at least some reduction in friction between internal surface58 of helmet shell 52 and the external surface 60 of headgear liner 56and/or to provide at least some channeling or directing of loading in apreferred direction upon the headgear liner 56 to enhance the absorptionof energy by the liner 56 and/or helmet assembly 50.

FIG. 8 is a top plan view of a liner assembly 74 that may be used forliner assembly 54 shown in FIGS. 6 and 7. FIG. 9 is a top plan view of aliner assembly 75 that may be used for liner assembly 54 shown in FIGS.6 and 7. FIG. 10 is a front perspective view of the liner assembly 75shown in FIG. 9. As shown in FIGS. 8, 9, and 10, liner assembly 74 or 75may comprise a headgear liner 76, for example, a fluid-filled headgearliner as disclosed in U.S. Pat. Nos. 8,856,972 and 10,531,699, and aplurality of interface elements 78, 80, 82, and 84, for example, similarto interface element 62 shown in FIGS. 6 and 7. As shown in FIGS. 8, 9,and 10, in one aspect, and similar to headgear liner 56, headgear liner76 may have a plurality of through holes 86 and may also have aplurality of radial slots 88 allowing the liner 76 to conform to, forexample, be manipulated and positioned into, the internal shape of ahelmet shell, such as, helmet shell 52. In one aspect, headgear liner 76may include a plurality of mounting pads 90, for example, hook-and-looptype pads, adapted to engage complementary pads mounted on the innersurface 58 of the helmet shell 52.

According to aspects of the invention interface elements 78, 80, 82, and84 are designed to modify, regulate, or channel the loads received bythe helmet shell 52 into which liner assembly 74 or 74 is positioned toenhance the performance of the helmet/liner assembly, for example, toreduce the loading transferred from the helmet shell to the head of thewearer. In one aspect, this modification, regulation, and/or channelingof loads is effected by providing surfaces of varying height orthickness on interface elements 78, 80, 82, and 84 whereby surfaces ofgreater height or thickness receive and direct loadings in desired,predetermined direction(s) upon the headgear liner 76.

Interface elements 78, 80, 82, and 84 may be mounted to headgear liner76 of liner assembly 74 or 75 by conventional means, for example, withfasteners, such as, hook-and-loop type fasteners, an adhesive, or moldedor otherwise formed into liner 76.

FIG. 11 is top plan view of one interface element 78 shown in FIGS. 8,9, and 10 according to one aspect of the invention. FIG. 12 is a sideelevation view of interface element 78 shown in FIG. 11 as viewed alongview lines 12-12 in FIG. 11; and FIG. 13 is a side elevation view ofinterface element 78 shown in FIG. 11 as viewed along view lines 13-13in FIG. 11. FIG. 14 is an exploded perspective view of interface element78 shown in FIG. 11.

Though interface element 78 (and any interface element disclosed herein)may be formed from a broad range of fabrication processes, for example,machining, stamping, 3-D printing, molding, laser cutting, and the like,in the aspect of the invention shown in FIGS. 11 through 14, interfaceelement 78 is fabricated by multiple components to facilitatedevelopment, fabrication and/or evaluation. In the aspect shown, themultiple components shown may be assembled by conventional means, forexample, with fasteners, adhesives, welding, or soldering, and the like.According to one aspect, the components of interface element 78 may befabricated with hook-and-loop type fasteners, for example, Velcro® brandhook-and-loop fasteners. In one aspect, the individual components ofinterface element 78 shown in FIGS. 11 though 14 may be fabricated bycutting the components from hook-and-loop type fastener material, forexample, from sheets or strips of hook-and-loop type fastener materials.

As shown in FIGS. 11 through 14, in one aspect, interface element 78(and any interface element disclosed herein) may include a base element92 and a plurality of guide elements 94, 96, 98, 100, 102, and 104mounted to base element 92. Though base element 92 and guide elements94, 96, 98, 100, 102, and 104 are shown generally polygonal in shapewith one or more rounded edges, the shapes of base element 92 and guideelements 94, 96, 98, 100, 102, and 104 may vary broadly while stillproviding the desired function. In one aspect, guide elements 94, 96,98, 100, 102, and 104 may comprise projections from base element 92, forexample, projections formed in or upon base element 92.

As shown most clearly in FIG. 14, guide element 94 may be mounted tobase element 92 and guide element 100 may be mounted to guide element 94to provide first and second contact surface A on guide element 100 andcontact surface B on guide element 94 as shown in FIG. 11. According toaspects of the invention, contact surface A on guide element 100 may be“higher than” or distal contact surface B where, upon impact of theadjacent helmet shell, contact surface A contacts and receives loadingprior to contact surface B. According to aspects of the invention, thisprior contact and loading, no matter how small the difference in contacttime, promotes the reception and transmission of a load upon contactsurface A on guide element 100 before the reception and transmission ofthe load to contact surface B on guide element 94. It is believed thatprior contact and loading on contact surface A promotes the transmissionof load to the adjacent liner, for example, to a fluid-containing liner,at a preferred time and in a desired, previously defined direction toenhance the energy absorbing capacity of the liner or helmet/linercombination. In one aspect, interface element 78 may only include onlyguide elements 94 and 100 on base element 92 to provide contact surfacesA and B only.

Similarly, in one aspect, as shown most clearly in FIG. 14, guideelements 96 and 98 may be mounted to base element 92 and guide elements102 and 104 may be mounted to guide elements 96 and 98, respectively, toprovide third contact surface C on guide element 102 and fourth contactsurface D on guide element 104 as shown in FIG. 11. Again, according toan aspect of the invention, contact surface C on guide element 102 andcontact surface D on guide element 104 may be “higher than” or distalcontact surface B on guide element 94 where, upon impact of the adjacenthelmet shell, contact surfaces C and D (depending upon the angle ofimpact) contact and receive loading prior to contact surface B. In theaspect of the invention shown in FIGS. 11 through 14, contact surfaces Cand D are shown located at about the same elevation of contact surface,wherein contact with surfaces A, C, and D may occur substantiallysimultaneously and induce substantially simultaneous fluid flows in theliner in the directions shown. However, in other aspects of theinvention, at least one of contact surfaces C and D (that is, eithercontact surface C or contact surface D or both) may be higher thancontact surface B, but lower than contact surface A, where, for example,the sequence of reception and transmission may comprise the sequence:surface A, then surface C and/or D, and then surface B. Again, accordingto aspects of the invention, this prior contact, reception, and/orloading, no matter how small the difference in contact time, promotesthe reception and transmission of a load upon contact surfaces oninterface element 78 that may be used to promote the transmission ofload to the adjacent liner at a preferred time and in a desired,previously defined direction to enhance the energy absorbing capacity ofthe liner or helmet/liner combination. In one aspect, interface element78 may only include guide elements 96 and 102 and/or guide elements 98and 104 on base element 92 to provide contact surfaces C and/or D only.

FIGS. 15 through 18 schematically illustrate the perceived effect ofaspects of the invention on the reception and transmission of load tothe liner 76 by interface element 78 shown in FIGS. 11 through 14according to one aspect of the invention. FIG. 15 is a plan view of aportion of headgear liner assembly 74 or 75 having headgear liner 76about interface element 78 as indicated by Detail 15 shown in FIGS. 8and 9. FIG. 15 also includes the respective contact surfaces A, B, C,and D disclosed and discussed with respect to FIGS. 11 through 14. FIG.16 is a cross-sectional view of the portion of headgear liner assembly74 or 75 shown in FIG. 15 as viewed along view lines 16-16 shown in FIG.15. According to one aspect, liner 76 of liner assembly 74 or 75 maytypically contain a fluid 77, such as, an oil or an alcohol.

In the aspect of the invention shown in FIGS. 15 and 16, for the sake ofillustration, contact surfaces C and D are positioned at an elevationsubstantially the same as the elevation of contact surface A, but higherthan contact surface B. In this aspect, the sequential reception andtransition of load from a helmet shell upon the contact surfaces ofinterface element 78 may comprise the sequence: surfaces A, C, and Dsubstantially simultaneously, and then surface B. In one aspect of theinvention, load may or may not be received and transmitted throughcontact with the helmet shell (not shown) with the surface of baseelement 92 of interface element 78.

As illustrated in FIGS. 15 and 16, and as described with respect toFIGS. 11 through 14, with the positioning and relative elevations ofsurfaces A, B, C, and D, for example, on interface element 78, thesequential impact of surfaces A, B, C, and, D on interface element 78can be used to control, regulate, and/or channel the transmission offorce from a helmet shell (not shown) to fluid 77 within headgear liner76. For example, as shown in FIG. 16, initial contact with or receptionby the most elevated or highest contact surface A by the force indicatedby arrow 110 in FIG. 16, interface element 78 can transmit the force nothrough interface element 78 to headgear liner 76 and to fluid 77. It isenvisioned that this localized loading or compression of liner 76, whichmay typically be flexible, can compress fluid 77 and promote a fluidflow in fluid 77 as indicated schematically by arrow 112 (that is, inthis example, in a direction out of the page of FIG. 16). According toaspects of the invention, this directed and sequential control and/orchanneling of flow of the fluid 77 within headgear liner 76 by receptionof load on contact surface A (or any other contact surface disclosedherein) enhances the absorption and/or dissipation of the force 110 byliner 76 to reduce the force transmitted to the head of the wearer.

FIG. 17 is a plan view of a portion of headgear liner assembly 74 or 75having headgear liner 76 about interface element 78 shown in FIGS. 15and 16 upon contact of surfaces C and D, for example, subsequent to thereception of force no on surface A or at substantially the same time asreception of force no on surface A. FIG. 18 is a cross-sectional view ofthe portion of headgear liner assembly 74 or 75 as viewed along viewlines 18-18 shown in FIG. 17, similar to the cross section shown in FIG.16. In a fashion similar to that shown in FIGS. 15 and 16, in the aspectof the invention shown in FIGS. 17 and 18, contact surfaces C and D arepositioned at an elevation about the same as contact surface A, thoughin one aspect, contact surfaces C and D may be both lower or both higherthan the elevation contact surface A, but higher than contact surface B.In one aspect, the elevations of contact surfaces C and D of interfaceelement 78 may also be different.

As illustrated in FIGS. 17 and 18, and as described with respect toFIGS. 11 through 14, with the positioning and relative elevations ofsurfaces A, B, C, and D, the impact of loads on surfaces C and Dsubstantially simultaneous with or after reception and transition offorce no on contact surface A, the reception of forces upon surfaces Cand D may be indicated by arrows 114 and 116, respectively, in FIG. 18.Again, according to an aspect of the invention, the reception andtransmission of forces 114 and 116 on contact surfaces C and D,respectively, can transmit force through interface element 78 toheadgear liner 76 to promote a fluid flow in fluid 77 as indicatedschematically by arrows 118 and 120 (that is, in a direction out of thepage of FIG. 18), for example, in a direction substantially parallel tothe plane of the first contact surface A. According to aspects of theinvention, this sequential and directed flow control and/or channelingof flow of the fluid 77 within headgear liner 76 can enhance theabsorption and/or dissipation of the forces 114 and 116 by liner 76 toreduce the force transmitted to the head of the wearer. In addition, inone aspect, the simultaneous or subsequent reception of load by surfaceB of interface element 76 may promote a fluid flow and energydissipation and/or absorption in fluid 77 as indicated schematically byarrow 122 shown in FIG. 17.

It is to be understood that the directions of flow illustrated by arrows112, 118,120, and 122 in FIGS. 15 through 18 are examples only tofacilitate disclosure of aspects of the invention. It is envisioned thatthese directions of fluid flow may vary depending, among other things,upon the presence of adjacent structures within the fluid-filled liner76 (for example, a liner sidewall or a through-hole sidewall) and thedirection of impact of the load upon the helmet shell. For example, itis envisioned that in some aspects of the invention the direction offluid flow induced within the fluid-filled liner 76 may be differentfrom the directions indicated by arrows 112, 118, 120, and 122. Forinstance, it is envisioned that the flows may be in an oppositedirection to the direction of arrows 112, 118, 120, and 122, forexample, as indicated by arrows 124 and 126 in FIGS. 15 and 17. Inaddition, it is envisioned that the direction of fluid flow inducedwithin the fluid-filled liner 76 may be in a non-orthogonal direction orin an oblique direction, that is, in any direction not represented byarrows 112, 118, 120, 122, 124, and 126.

FIG. 19 is top, plan view of another interface element 82 shown in FIGS.8 and 9 according to an aspect of the invention. FIG. 20 is a sideelevation view of interface element 82 shown in FIG. 19 as viewed alongview lines 20-20 shown in FIG. 19; and FIG. 21 is a side elevation viewof interface element 82 shown in FIG. 19 as viewed along view lines21-21 shown in FIG. 19.

As descried with respect to interface element 78, interface element 82may be formed from a broad range of fabrication processes, for example,machining, stamping, 3-D printing, molding, laser cutting, and the like.In the aspect of the invention shown in FIGS. 19 through 21, interfaceelement 82 is fabricated by multiple components to facilitatedevelopment, fabrication, and/or evaluation. In the aspect shown, themultiple components shown may be assembled by conventional means, forexample, with fasteners, adhesives, welding or soldering, and the like.According to one aspect, the components of interface element 82, in afashion similar to interface element 78, may be fabricated withhook-and-loop type fasteners, for example, by cutting the componentsfrom hook-and-loop type fastener material, for example, from sheets orstrips of hook-and-loop type fasteners.

As shown in FIGS. 19 through 21, in one aspect, interface element 82 mayinclude a base element 132 and a plurality of guide elements 134, 136and 138 each shaped as shown and mounted to base element 132. Thoughbase element 132 and guide elements 134, 136, and 138 are showngenerally polygonal in shape with one or more rounded edges, the shapesof base element 132 and guide elements 134, 136, and 138 may varybroadly while still providing the desired function.

As shown most clearly in FIGS. 19 and 20, guide element 134 is mountedto base element 132, for example, with or without one or more spacerelements 135, and guide elements 136 and 138 are mounted to base element132 to provide a first contact surface A on guide element 134, a secondcontact surface B on guide element 136, and a third contact surface C onguide element 138 as shown in FIG. 19. According to the aspect of theinvention shown in FIGS. 19 through 21, contact surface A on guideelement 134 may be “higher than” or distal to contact surfaces B and C,where, upon impact of the adjacent helmet shell (not shown), contactsurface A receives a force, as indicated by arrow 140 in FIG. 21, andtransmits the force 140 prior to contact surfaces B and C.

According to aspects of the invention, this prior contact and loadingindicated by arrow 140, no matter how small the difference in contacttime, promotes the reception and transmission of a load upon contactsurface A on guide element 134 before the reception and transmission ofthe load to contact surfaces B on guide element 16 and contact surface Con guide element 138. According to aspects of the invention, it isbelieved that prior contact and loading on contact surface A promotesthe transmission of load to the adjacent liner, for example, afluid-containing liner, and to the fluid the liner contains, as indicateby arrow 142 in FIG. 19, at a preferred time and in a desired,previously defined direction to enhance the energy absorbing capacity ofthe liner or helmet/liner combination. In one aspect, interface element82 may only include guide element 134 having contact surface A on baseelement 132 to provide contact surfaces A and D only.

Similarly, in one aspect, as shown most clearly in FIG. 19, guideelements 136 and 138 may be mounted to base element 132 to providecontact surfaces B and C on guide elements 136 and 138. In one aspect,contact surface D may be provided on base element 132 as shown in FIG.19. Again, according aspect of the invention, contact surface B on guideelement 136 and contact surface C on guide element 138 may be “higherthan” or distal contact surface D on base element 132 and higher than,lower than, or substantially equal in elevation to contact surface A onguide element 134. According to an aspect of the invention, upon impactof the adjacent helmet shell (not shown), contact surfaces C and D(depending upon the angle of impact) receive loading after, prior to, orat substantially the same time as to contact surface A. This loading oncontact surfaces B and C is represented by arrows 144 and 146,respectively, shown in FIG. 21.

In the aspect of the invention shown in FIGS. 19 through 21, contactsurfaces C and D are shown located at a lower elevation of contactsurface A wherein reception of load on contact surface A, as indicatedby arrow 140, precedes reception of load on contact surfaces B and C, asindicated by arrows 144 and 146, respectively. In one aspect, depending,for example, upon the thickness of elements 132, 135, 134, 136, and 138,the reception of load on contact surfaces B and C (arrows 144 and 146)may follow, may precede, or may occur at substantially the same time asreception of the load (arrow 140) on contact surface A. In one aspect ofthe invention, at least one of contact surfaces B or C (that is, eithercontact surface B or contact surface C or both) may be higher thancontact surface D, but lower than contact surface A, where, for example,the sequence of contact and transmission may be: surface A, then surfaceB and/or C, and then surface D. Again, according to aspects of theinvention, this prior contact and loading, no matter how small thedifference in contact time, promotes the reception and transmission of aload upon contact surfaces on interface element 82 that may be used topromote the transmission of load to the adjacent liner and to the fluid77 the liner contains, as indicated by arrows 148 and 150, respectively,in FIG. 19 at a preferred time and in a desired, previously defineddirection to enhance the energy absorbing capacity of the liner orhelmet/liner combination. In one aspect, interface element 82 may onlyinclude guide element 136 and/or guide element 138 on base element 132to provide contact surfaces B and/or C only.

FIG. 22 is top, plan view of another interface element 84 shown in FIGS.8 and 9 according to an aspect of the invention. Interface element 84shown in FIG. 22 may be a mirror image of interface element 80 shown inFIGS. 8 and 9 according to one aspect of the invention. FIG. 23 is aside elevation view of interface element 84 shown in FIG. 22 as viewedalong view lines 23-23 shown in FIG. 22; and FIG. 24 is a side elevationview of interface element 84 shown in FIG. 22 as viewed along view lines24-24 shown in FIG. 22.

As descried with respect to interface elements 78 and 82, interfaceelement 84 and interface element 80 may be formed from a broad range offabrication processes, for example, machining, stamping, 3-D printing,molding, laser cutting, and the like. In the aspect of the inventionshown in FIGS. 22 through 24, interface element 84 is fabricated bymultiple components to facilitate development, fabrication, and/orevaluation. In the aspect shown, the multiple components shown may beassembled by conventional means, for example, with fasteners, adhesives,welding or soldering, and the like. According to one aspect, thecomponents of interface element 84, in a fashion similar to interfaceelements 78 and 82, may be fabricated with hook-and-loop type fasteners,for example, by cutting the components from hook-and-loop type fastenermaterial, for example, from sheets or strips of hook-and-loop typefasteners.

As shown in FIGS. 22 through 24, in one aspect, interface element 84 mayinclude a base element 152 and a plurality of guide elements 154, 156,158, and 160, each shaped as shown and mounted to base element 152.Though base element 152 and guide elements 154, 156, 158, and 160 areshown generally polygonal in shape with one or more rounded edges, theshapes of base element 152 and guide elements 154, 156, 158, and 160 mayvary broadly while still providing the desired function.

As shown most clearly in FIGS. 23 and 24, guide elements 154, 156, 158,and 160 may be mounted to base element 152, for example, with or withoutone or more spacer elements (not shown), and guide element 156 may bemounted to one or more guide elements 154, 158, and/or 160 to provide afirst contact surface A on guide element 156, a second contact surface Bon guide element 160, a third contact surface C on guide element 154,and a fourth contact surface D on guide element 158, as shown in FIG.22. In one aspect, the surface of base element 152 may comprise a fifthcontact surface E.

According to the aspect of the invention shown in FIGS. 22 through 24,contact surface A on guide element 156 is “higher than” or distal tocontact surfaces B, C, D, and E, where, upon impact of the adjacenthelmet shell (not shown), contact surface A receives a force, asindicated by arrow 162 in FIG. 24, and transmits loading prior tocontact surfaces B, C, D, and E. According to aspects of the invention,this prior contact and loading indicated by arrow 162, no matter howsmall the difference in contact time, promotes the reception andtransmission of a load upon contact surface A on guide element 156before the reception and transmission of the load to contact surfaces Bon guide element 160, contact surface C on guide element 154, contactsurface D on guide element 158, and contact surface E on base element152. According to aspects of the invention, it is believed that priorcontact and loading on contact surface A promotes the transmission ofthe force 162 to the adjacent liner, for example, a fluid-containingliner, and to the fluid in the liner contains, as indicate by arrow 164,at a preferred time and in a desired, previously defined direction toenhance the energy absorbing capacity of the liner or helmet/linercombination. In one aspect, interface element 84 may only include guideelement 156 having contact surface A on base element 152 to providecontact surfaces A and E only.

Similarly, in one aspect, as shown most clearly in FIG. 22, guideelements 154, 158, and 160 may be mounted to base element 152 to providecontact surfaces B, C, and D on guide elements 160, 154, and 158,respectively. In one aspect, contact surface E may be provided on baseelement 152 as shown in FIG. 22. Again, according to this aspect of theinvention, contact surface B on guide element 160, contact surface C onguide element 154, and/or contact surface D on guide element 158 may be“higher than” or distal contact surface E on base element 152 and higherthan, lower than, or substantially equal in elevation to contact surfaceA on guide element 156 (for example, with one or more appropriativespacer elements, not shown). According to aspect of the invention, uponimpact of the adjacent helmet shell (not shown), contact surfaces B, C,D and/or E (depending upon the angle of impact) may receive loadingbefore, after, or substantial at the same time as to contact surface A.Arrows 166 and 168 represent this loading on contact surfaces C and D,respectively, shown in FIG. 24.

In the aspect of the invention shown in FIGS. 22 through 24, contactsurfaces B, C, and D are shown located at a lower elevation of contactsurface A wherein reception of load on contact surface A, as indicatedby arrow 162, precedes reception of load on contact surfaces B, C, andD, as indicated by arrows 166 and 168, respectively. In one aspect,depending, for example, upon the thickness of elements 152, 154, 156,158, and 160, the reception of load on contact surfaces B, C, and D(arrows 166 and 168) may follow, may precede, or may occur atsubstantially the same time as reception of the load (arrow 162) oncontact surface A. In one aspect of the invention, at least one ofcontact surfaces B, C, or D (that is, either contact surface B orcontact surface C or contact surface D or all three) may be higher thancontact surface E, but lower than contact surface A, where, for example,the sequence of contact and transmission may be: surface A, then surfaceB and/or C and/or D, and then surface E.

Again, according to aspects of the invention, this prior contact andloading, no matter how small the difference in contact time, promotesthe reception and transmission of a load upon contact surfaces oninterface element 84 that may be used to promote the transmission ofload to the adjacent liner and to the fluid the liner contains, asindicated by arrows 170, 172, and 174, respectively, shown in FIG. 22,at a preferred time and in a desired, previously defined direction toenhance the energy absorbing capacity of the liner or helmet/linercombination. In one aspect, interface element 84 may only include one ormore of guide elements 154 and/or guide element 158 and/or guide element160 on base element 152 to provide contact surfaces B and/or C and/or Donly.

In one aspect of the invention, the location, orientation, and/ordirection of interface elements 78, 90, 82, and 84 on headgear linersmay be chosen to direct or channel fluid flow within a liner about oraround any internal structures in the fluid-filled liner. For example,as shown in FIG. 8 and FIG. 22, interface elements 84 having guideelements 154, 156, 158, and 160 may be positioned to direct flow aroundor past internal hole side walls 180 and 182 (shown in phantom in FIG.22) within a fluid-filled liner (not shown). Though FIG. 22 shows thisaspect for interface element 84, interface elements 78, 80, and 82 mayalso be located, orientated, and/or directed to provide guide elementsthat channel or direct flow in a direction that avoids or circumventsany internal structures within a fluid-filled liner. These internalstructures may include sidewalls of holes or cavities, baffles, andliner sidewalls, among other internal structures that may be foundwithin a liner, such as, a fluid-filled liner.

Interface elements 78, 80, 82, and 84 may comprise a broad range ofmaterials and material surface textures. For example, in one aspect,interface elements 78, 80, 82, and 84 may comprise a plastic, forexample, a polyamide (PA), for example, nylon; a polyethylene (PE), bothhigh-density polyethylene (HDPE) and low-density polyethylene (LDPE); apolyethylene terephthalate (PET); a polypropylene (PP); a polyester(PE); a polytetrafluoroethylene (PTFE); a polystyrene (PS); anacrylonitrile butadiene styrene (ABS); a polycarbonate (PC); or apolyvinylchloride (PVC); among other plastics. In another aspect,interface elements 78, 80, 82, and 84 may comprise an elastic material,such as, a rubber or an elastomer, for example, a natural polymer, suchas, polyisoprene rubber, or a synthetic polymer, such as, a neoprene, athermoplastic elastomer, a thermoplastic rubber, and a polyvinylchloride, or an ethylene propylene diene monomer (EPDM) rubber, and thelike. In another aspect, interface elements 78, 80, 82, and 84 maycomprise a wood (for example, in the form of paper) or a metal, whileproviding the desired reduction in friction.

In one aspect of the invention, interface elements 78, 80, 82, and 84may be flexible or pliant, for example, readily conforming to the shapeand texture of the internal surface 58 of helmet shell 52 (as shown inFIG. 7) and/or the external surface 70 of headgear liner 56 (as shown inFIG. 7). In one aspect, interface elements 78, 80, 82, and 84 maycomprise a woven or unwoven fabric, for example, a natural fabric suchas, cotton or wool, or a synthetic fabric, for example, fabricated fromthreads of any one or more of the plastics or polymers disclosed herein.

In one aspect, as disclosed herein, interface elements 78, 80, 82, and84 and their respective guide elements may be fashioned from ahook-and-loop type fastener material, for example, the same or adifferent hook-and-loop type fastener material. For instance, in oneaspect, interface elements 78, 80, 82, and 84 may comprise a “hookside,” a “loop side,” or both of a hook-and-loop type fastener material.

The hook-and-loop-type fasteners used for interface elements 78, 80, 82,and 84 may comprise a plastic hook-and-loop type fastener, for example,a nylon hook-and-loop type fastener, or a hook-and-loop type fastenermade of any one of the plastics disclosed herein. In one aspect, thehook-and-loop type fastener used for interface elements 78, 80, 82, and84 may be a Velcro® brand hook-and-loop-type fastener provided byVelcro, USA, for example, a nylon Velcro® hook-and-loop-type fastenerhaving model number 158505, or its equivalent.

As disclosed herein, interface elements 78, 80, 82, and 84 may have ageneral rounded rectangular shape or “race track oval” type shape. Inone aspect, interface elements 78, 80, 82, and 84 may have a dimension,that is, a length, width, or diameter, ranging from 0.25 inches to 12inches, depending, among other things, upon the size of liner 56, buttypically interface elements 78, 80, 82, and 84 may have a dimensionranging between 1 inch and 5 inches, for example, about 3 inches inlength and about 2 inches in width. Similarly, any of the guide elementsdisclosed herein, for example, guide elements 94, 96, 98, 100, 102, and104 shown in FIGS. 11 through 14, may have dimensions ranging between0.25 inches and 5 inches, for example, about 1 to 2 inches in length andabout 0.75 inch in width.

In one aspect, the thickness of interface elements 78, 80, 82, and 84and their respective guide elements may range from 0.03125 ( 1/32)inches to 2 inches, depending, among other things, upon the size of theliner they are mounted to, but interface elements 78, 80, 82, and 84 andtheir respective guide elements typically may have a thickness rangingbetween 0.0625 ( 1/16) inches and 0.5 inches. In one aspect, thedifference in height or elevation of one contact surface and anothercontact surface on interface elements 78, 80, 82, and 84 may range from0.001 inches to 0.25 inches. However, the difference in height orelevation of one contact surface and another contact surface oninterface elements 78, 80, 82, and 84 may typically range from 0.03125 (1/32) inches to 0.125 (⅛) inches.

FIG. 25 is a perspective view of a helmet assembly 200 according to afurther aspect of the invention. FIG. 26 is an exploded perspective viewof the helmet assembly 200 shown in FIG. 25. As shown in FIGS. 25 and26, helmet assembly 200 includes a helmet shell 202, one or moreinterface elements 204 shaped to be received by and positioned in helmetshell 202, and helmet liner 206 positioned within interface element 204.As discussed above, according to aspects of the invention, an interfaceelement may extend substantially completely over the external surface ofa fluid-filled liner. Helmet assembly 200 shown in FIGS. 25 and 26 is anexample of a helmet assembly having one such interface element 204 whichextends substantially completely over the external surface of thefluid-filled liner 206. In one aspect, interface element 204 with orwithout liner 206 may be referred to as a “bump cap.”

According to this aspect, though this aspect shown in FIGS. 25 and 26may be reoffered to as a “helmet assembly,” assembly 200 may compriseany form of headgear assembly, as disclosed herein.

Helmet shell 202 may comprise any one of the helmet shells disclosedherein. As shown in FIGS. 25 and 26, helmet shell 202 may typicallyinclude an external surface 208 and an internal surface 210. As in otheraspects of the invention, helmet shell 202 may comprise any one or moreof the plastics disclosed herein, for example, a polycarbonate.

As descried with respect to interface disclosed herein, one or moreinterface elements 204 may be formed from a broad range of fabricationprocesses, for example, machining, stamping, 3-D printing, molding,laser cutting, and the like. As shown in FIGS. 25 and 26, the one ormore interface elements 204 typically include an external surface 212and an internal surface 214. As also shown in FIGS. 25 and 26, interfaceelement 204, in this case which may be referred to as a “bump cap,” maytypically be sized and shaped to be received by helmet shell 202, forexample, having a generally hemispherical shape reflecting the generallyhemispherical shape of the internal surface 210 of helmet shell 202.However, it is envisioned that the shape and size of the one or moreinterface elements 204 may comprise any configuration, size, and/orshape that is compatible with the shape of the helmet shell 202 or theshape of the internal surface 210 of helmet shell 202. For example,according to an aspect of the invention where the one or more interfaceelements 204 provide at least some form of reduced friction betweenhelmet liner 204 and helmet shell 202, the one or more interfaceelements 204 may typically be shaped where the external surface 212 ofthe one or more interface elements 204 is shaped to generally contactand/or bear against the internal surface 210 of helmet shell 202. In oneaspect, the shape of interface elements 204 may be provided where atleast 50% of the area of the external surface 212 may contact and/orbear against the internal surface 210 of helmet shell 202. In anotheraspect, the shape of the one or more interface elements 204 may beprovided where at least 75%, or at least 90%, of the area of theexternal surface 212 may contact and/or bear against the internalsurface 210 of helmet shell 202.

Though in FIG. 26, interface element 204 is shown as one integral part,in one aspect, interface element 204 may comprise two or more parts orcomponents, for example, two or more separate or interlockingcomponents. The thickness of interface element 204 may be similar to thethicknesses of any of the interface eluents disclosed herein, forexample, having a thickness ranging between 0.0625 ( 1/16) inches and0.5 inches. As in other aspects of the invention, interface element 204may comprise any one or more of the plastics disclosed herein, forexample, an ABS plastic or a PTFE-containing plastic.

As shown most clearly in FIG. 26, according to one aspect of theinvention, interface element 204 may include one or more, but typically,a plurality of, projections or pins 216 from the internal surface of214. According aspects of the invention, the one or more projections 216are positioned and adapted to engage recesses or holes 218 in helmetliner 206. The engagement of projections 216 with recesses or holes 218may at least partially assist in positioning and/or retaining helmetliner 206 within interface element 204. In one aspect, projections orpins 216 may be integrally formed into the surface 214 of interfaceelement 204, for example, molded, machined, or otherwise fabricated fromthe same material, for example, a plastic, as interface element 214.

As also shown in FIG. 26, interface element 204 may include features orstructures that assist in mounting and/or retaining the one or moreinterface elements 204 within helmet shell 202. For example, as shown inFIG. 26, interface element 204 may include one or more recesses,cavities, or holes 217 sized, positioned, and otherwise adapted toengage a retaining device or retaining assembly, for example, a harness,a suspension, or a retainer mounted in helmet shell 202.

Though shown generally circular cylindrical, for example, right circularcylindrical, in shape in FIG. 26, projections or pins 216 may compriseany appropriate cylindrical shape, including elliptical (or oval)cylindrical or polygonal cylindrical (including triangular, square, orhexagonal cylindrical). In one aspect, projections or pins 216 may benon-right cylindrical, for example, having a taper (for example, beingfrusto-conical in shape). In one aspect, the tapered shape ofprojections or pins 216 may assist in retaining the liner 206 withininterface element 204. In one aspect, the tapered pins 216 may have alarger dimension at the bottom or at the surface 214 of interfaceelement 204; in another aspect, the tapered pins 216 may have a largerdimension at the top or distal the surface 214 of interface element 204.

Projections or pins 216 may have width, diameter, or outer dimensionranging from about 0.0625 ( 1/16) inches to about 3 inches, but theouter dimension may typically between about 0.125 inches to about 1.5inches. Projections or pins 216 may have length (or height from surface214) ranging from about 0.125 inches to about 3 inches, but is typicallybetween about 0.25 inches to about 1 inch in length.

Projections or pins 216 may be made from any one or more of thematerialists disclosed herein, for example, any one or more of theplastics or elastomers disclosed herein. In one aspect, projections orpins 216 may be made of a low-density compressible material, forexample, a plastic foam material, such as, expanded polypropylene (EPP),or its equivalent.

As shown in FIGS. 25 and 26, helmet liner 206 may be any liner orinterface shaped and adapted to be received by interface element 204 andthe head of a wearer (not shown). As shown in FIG. 26, helmet liner 206may typically include an external surface 220 and an internal surface222. Helmet liner 206 may comprise any one of the fluid-containingliners disclosed herein, for example, liner 16 or liner 56 disclosedherein, or a fluid-filled headgear liner disclosed in U.S. Pat. No.8,856,972 or U.S. Pat. No. 10,531,699; or in pending U.S. applicationSer. Nos. 16/595,135; 16/738,234; 17/020,888; or 17/015,738. Helmetliner 206 may be formed from a liquid silicone rubber (LSR), forexample, a cured LSR. In one aspect, helmet liner 206 may be comprise a“medical grade” LSR, as known in the art, for example, a LSR marketed byCHT USA (formerly Quantum Silicones (QSi)) under the trademark TrueSkin® or its equivalent; however, helmet liner 206 may comprises anyliquid silicone rubber (LSR).

In one aspect, the fluid in helmet liner 206 may comprise apolydimethylsiloxane fluid, for example, a polydimethylsiloxane fluidmarketed by CHT USA as a QM Diluent or its equivalent; however, liquid14 may comprise any polydimethylsiloxane fluid. However, in otheraspects, the fluid in helmet liner 206 may be any fluid, including anoil or water, such as, distilled water.

FIG. 27 is a plan view of the fluid-filled helmet liner 206 shown inFIG. 26. As shown in FIGS. 26 and 27, helmet liner 206 may comprise acentral portion and a plurality of “lobes” 226 extending from thecentral portion 224, the lobes 226 may be delimited by radial recesses228. According to an aspect of the invention, the central portion 224,lobes 226, and recesses 228 allow the typically malleable liner 206 tobe manipulated and shaped to be inserted within the interface element^(204.)

As also shown in FIG. 27, helmet liner 226 may include recesses or holes218 shaped and positioned to engage projections or pins 216, asdisclosed herein. Recesses 218 may extend through liner 226, forexample, through holes, or may comprise recesses, for example, “blindholes,” in liner 226. The dimension of recesses or holes 218 may becomparable to the dimension of projections 216, for example, to ensureelastic engagement. For example, recesses or holes 218 may be circular,elliptical, or polygonal in cross section, and may have an insidediameter or inside dimension ranging from about 0.0625 ( 1/16) inches toabout 3 inches, but the outer dimension of recesses or holes 218 maytypically between about 0.125 inches to about 1.5 inches.

As also shown in FIG. 27, helmet liner 226 may include recesses or holes230, for example, extending through the liner 226. Holes 230 may becircular or non-circular in cross section, and have an inside diameteror dimension ranging from 0.125 inches to 3 inches, but typically havean inside dimension ranging from 0.25 inches to 1 inch.

As disclosed herein, helmets, headgear, headgear liners, helmet linerassemblies, and methods of protecting the head are provided havinginterface elements, for example, friction-reducing interface elements orpads having load directing guide elements that enhance head protectionand provide improvements over the existing helmet or headgeartechnology.

Though aspects of the invention may have been described in the contextof helmets or headgear, it is envisioned that aspects of the inventioncan be applied to any form of head protection that could benefit fromaspects of the invention. For example, it is envisioned that aspects ofthe invention may be implemented in, and thus may comprise, a baseballcatcher's helmet, a baseball batter's helmet, a soft ball catcher'shelmet, a softball batter's helmet, a hockey helmet, a hockey goaliemask, a motorcycle helmet, a motor cross helmet, a skiing helmet, asnowboarding helmet, a skateboarding helmet, a lacrosse helmet, abicycle helmet, a jockey helmet, an official's helmet, a medicalprotection helmet, a rock or ice climbing helmet, a mining helmet, amountain climbing helmet, a football helmet, a construction helmet, ahard hat, and a military helmet, among others. It is also envisionedthat aspects of the invention may be implemented in, and thus maycomprise, a bump cap, as known in the art.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiments were chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

While several embodiments and aspects of the present invention have beendescribed and depicted herein, alternative aspects may be affected bythose skilled in the art to accomplish the same objectives. Accordingly,it is intended by the appended claims to cover all such alternativeaspects as fall within the true spirit and scope of the invention.

1. A headgear assembly comprising: a helmet shell shaped to generallyconform to the head of a wearer, the helmet shell having an externalsurface and an internal surface; a headgear liner shaped and adapted tobe received by the helmet shell, the head gear liner having an externalsurface; and at least one interface element positioned between theexternal surface of the headgear liner and the internal surface of thehelmet shell, the at least one interface element providing at least somereduction in friction between the external surface of the headgear linerand the internal surface of the helmet shell.
 2. The headgear assemblyas recited in claim 1, wherein the headgear liner comprises afluid-filled headgear liner.
 3. The headgear assembly as recited inclaim 1, wherein the at least one interface element comprises a firstsurface positioned to face the helmet shell and at least one secondsurface positioned to face the helmet shell, the at least one secondsurface distal the first surface. 4-10. (canceled)
 11. The headgearassembly as recited in claim 2, wherein the fluid-filled headgear linercomprises a flexible, fluid impermeable enclosure having opposing endwalls, and a sidewall extending between the opposing end walls. 12-16.(canceled)
 17. A headgear liner assembly comprising: a headgear linercomprising a flexible, fluid impermeable enclosure having opposing endwalls, a sidewall extending between the opposing end walls, and a fluidcontained in the enclosure; and at least one interface element mountedto the headgear liner, the at least one interface element providing atleast some reduction in friction between the headgear liner and aninternal surface of a helmet shell into which the headgear liner ispositioned.
 18. The headgear liner assembly as recited in claim 17,wherein the at least one interface element comprises a plurality ofinterface elements mounted to the external surface of the headgearliner. 19-45. (canceled)
 46. The headgear assembly as recited in claim1, wherein the at least one interface element extends over more than 50%of a surface area of the external surface of the headgear liner.
 47. Theheadgear assembly as recited in claim 46, wherein the at least oneinterface element extends over more than 80% of the surface area of theexternal surface of the headgear liner.
 48. The headgear assembly asrecited in claim 47, wherein the at least one interface elementcomprises a bump cap.
 49. The headgear assembly as recited in claim 1,wherein the at least one interface element further comprises a pluralityof projections from the internal surface of the at least one interfaceelement, and wherein the headgear liner further comprises a plurality ofrecesses, each of the plurality of recesses positioned and adapted toengage one of the plurality of projections
 50. The headgear assembly asrecited in claim 49, wherein the plurality of recesses in the headgearliner comprises a plurality of through holes.
 51. The headgear assemblyas recited in claim 49, wherein engagement of the plurality ofprojections with the plurality of recesses at least partially retainsthe headgear liner within the at least one interface element.
 52. Theheadgear assembly as recited in claim 49, wherein the plurality ofprojections from the internal surface of the at least one interfaceelement comprises a plurality of pins.
 53. The headgear liner assemblyas recited in claim 17, wherein the at least one interface elementextends over more than 50% of a surface area of an external surface ofthe headgear liner.
 54. The headgear liner assembly as recited in claim53, wherein the at least one interface element extends over more than80% of the surface area of the external surface of the headgear liner.55. The headgear liner assembly as recited in claim 54, wherein the atleast one interface element comprises a bump cap.
 56. The headgear linerassembly as recited in claim 17, wherein the at least one interfaceelement further comprises a plurality of projections from the internalsurface of the at least one interface element, and wherein the headgearliner further comprises a plurality of recesses, each of the pluralityof recesses positioned and adapted to engage one of the plurality ofprojections.
 57. The headgear liner assembly as recited in claim 56,wherein the plurality of recesses in the headgear liner comprises aplurality of through holes.
 58. The headgear liner assembly as recitedin claim 56, wherein engagement of the plurality of projections with theplurality of recesses at least partially retains the headgear linerwithin the at least one interface element.
 59. The headgear linerassembly as recited in claim 56, wherein the plurality of projectionsfrom the internal surface of the at least one interface elementcomprises a plurality of pins.